Abstract
A simple method of producing alloy steels by mixing, pressing, and sintering iron powder with carbides of transition metals is described. The carbides must have a high carbon content and be soluble in iron. These characteristics are found in the carbides of chromium, tungsten, molybdenum, and vanadium. Tensile strengths of ∼800 N/mm2 have been achieved in annealed specimens having carbide additions of 1–12 wt.-%, depending on the carbide. The additions produce steels with partly air-hardening properties.
The effects of concentration and particle size of the carbides, sintered density, sintering conditions, and cooling rate on mechanical properties have been determined. The alloys are not very sensitive to the sintering atmosphere. The effect of heat-treatment on the mechanical properties of Fe-Cr3C2 alloys is reported. A tensile strength >1300 N/mm2 was observed with 4 wt.-% Cr3C2. Dilatometric measurements were conducted with different carbide concentrations and heating conditions to study the sintering process. The important process of homogenization was investigated by electron microprobe analysis.
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